Add metric for Internal Exceptions and refactor Node Status metrics

[suhailpatel]

Node Status metrics now have a separate tag for up and down, and then live/joining/leaving/unreachable status

This means we go from this

seastat_storage_node_status{node="172.17.0.2",status="live"} 1

To this

seastat_storage_node_status{node="172.17.0.2",state="up",status="live"} 1

Do note that previously if a node was joining/leaving, we would emit two metrics

seastat_storage_node_status{node="172.17.0.2",status="live"} 1
seastat_storage_node_status{node="172.17.0.2",status="joining"} 1

This was confusing and now we emit a single metric of the actual state

seastat_storage_node_status{node="172.17.0.2",state="up",status="live"} 1

[suhailpatel]

The most recent commit also adds a new metric

seastat_storage_node_host_id{id="08230342-67da-49f5-b58d-7efe49b72cf9",node="172.17.0.2"} 1

This is so you can get all the Node IDs for all nodes that are part of the actual ring